If your first 3 exams are worth 60% you get a 70, 68, and 60. Your 4th exam is worth 30% and your attendance is worth 10% you have not missed any days. What is your grade in the class, if you make a 90 or 80 on the final?
Can you assume that perfect attendance = 100? What did you get on the 4th exam?
.6(70 + 68 + 60)/3 + .3(?) + .1(100) = ?
Something is wrong. Without the final, you have accounted for 100% of your grade. If this is true, you don't need to take a final.
Without knowing the cutting points for the grades, it is impossible to answer your question.
Repost your problem with the information stated more accurately.